When a capacitive touch panel is applied to a large scale device, a number of sensing lines is increasing. Furthermore, requirements for accelerating sensing speed and calculating scan results are also increasing.
In an axis intersect (AI) capacitance sense technology, a coordinate of a touch is detected by a self-capacitance sensing method. However, a problem of ghost point occurs in the AI capacitance sense technology. As a result, a multi-point touch cannot be detected. In contrast, in an all-points addressable (APA) capacitance sense technology, a coordinate of a touch is usually detected by a mutual-capacitance sensing method. Accordingly, a multi-point touch can be detected in the APA capacitance sense technology.
Please refer to FIG. 1. FIG. 1 is a conventional capacitive touch device 10 by utilizing the AI capacitance sense technology. The capacitive touch device 10 comprises a touch panel 100 and a plurality of touch integrated circuits (IC) 102, 104. The touch panel 100 comprises a plurality of sensing lines S1-S20. The touch IC 102 is electrically coupled to the sensing lines S1-S10 for scanning the sensing lines S1-S10. The touch IC 104 is electrically coupled to the sensing lines S11-S20 for sensing the sensing lines S11-S20. Please refer to FIG. 2. FIG. 2 is a schematic diagram showing that the sensing lines S8-S13 and the touch ICs 102, 104 in FIG. 1. The sensing lines S10, S11 are regarded as boundary sensing lines. In the capacitive touch device 10, the position of a touch is determined by sensing two adjacent sensing lines. For example, the sensing lines S8 and S9 are charged and discharged for acquiring two analog-to-digital (ADC) values of the sensing lines S8 and S9. Then, the position of a touch between the sensing lines S8 and S9 is determined by the ADC values of the sensing lines S8 and S9. Similarly, the position of a touch between the sensing lines S9 and S10 is determined by ADC values of the sensing lines S9 and S10. The position of a touch between the sensing lines S10 and S11 is determined by ADC values of the sensing lines S10 and S11. However, the touch IC 102 is not electrically coupled to the sensing line S11, and thus the touch IC 102 cannot acquire the ADC values of the sensing line S11. When the position of the touch (between the sensing lines S10 and S11) is determined by only the ADC values of the sensing line S10, it is incorrect or small. In order to determine the correct position, the ADC values of the sensing line S11 acquired by the touch IC 104 is transmitted to the touch IC 102, such that the touch IC 102 is capable of determining the position between the sensing lines S10 and S11 by utilizing the ADC values of the sensing lines S10 and S11. Because the ADC values of the sensing line S11 have to be transmitted to the touch IC 102, the frame rate of the touch panel 100 is reduced significantly and thus performance of the capacitive touch device 10 is worse. For all-points addressable (APA) capacitance sense technology, a row of ADC values have to be transmitted to the touch IC 102, such performance suffering will become worst as well.
Therefore, there is a need for a solution to solve the above-mentioned problem that the frame rate is reduced significantly because one of two adjacent touch ICs transmits the ADC values of one boundary sensing line to the other of the two adjacent touch ICs.